1 /* 2 * processor_thermal.c - Passive cooling submodule of the ACPI processor driver 3 * 4 * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com> 5 * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com> 6 * Copyright (C) 2004 Dominik Brodowski <linux@brodo.de> 7 * Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> 8 * - Added processor hotplug support 9 * 10 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 11 * 12 * This program is free software; you can redistribute it and/or modify 13 * it under the terms of the GNU General Public License as published by 14 * the Free Software Foundation; either version 2 of the License, or (at 15 * your option) any later version. 16 * 17 * This program is distributed in the hope that it will be useful, but 18 * WITHOUT ANY WARRANTY; without even the implied warranty of 19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 20 * General Public License for more details. 21 * 22 * You should have received a copy of the GNU General Public License along 23 * with this program; if not, write to the Free Software Foundation, Inc., 24 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. 25 * 26 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 27 */ 28 29 #include <linux/kernel.h> 30 #include <linux/module.h> 31 #include <linux/init.h> 32 #include <linux/cpufreq.h> 33 #include <linux/proc_fs.h> 34 #include <linux/seq_file.h> 35 #include <linux/sysdev.h> 36 37 #include <asm/uaccess.h> 38 39 #include <acpi/acpi_bus.h> 40 #include <acpi/processor.h> 41 #include <acpi/acpi_drivers.h> 42 43 #define ACPI_PROCESSOR_COMPONENT 0x01000000 44 #define ACPI_PROCESSOR_CLASS "processor" 45 #define _COMPONENT ACPI_PROCESSOR_COMPONENT 46 ACPI_MODULE_NAME("processor_thermal"); 47 48 /* -------------------------------------------------------------------------- 49 Limit Interface 50 -------------------------------------------------------------------------- */ 51 static int acpi_processor_apply_limit(struct acpi_processor *pr) 52 { 53 int result = 0; 54 u16 px = 0; 55 u16 tx = 0; 56 57 58 if (!pr) 59 return -EINVAL; 60 61 if (!pr->flags.limit) 62 return -ENODEV; 63 64 if (pr->flags.throttling) { 65 if (pr->limit.user.tx > tx) 66 tx = pr->limit.user.tx; 67 if (pr->limit.thermal.tx > tx) 68 tx = pr->limit.thermal.tx; 69 70 result = acpi_processor_set_throttling(pr, tx); 71 if (result) 72 goto end; 73 } 74 75 pr->limit.state.px = px; 76 pr->limit.state.tx = tx; 77 78 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 79 "Processor [%d] limit set to (P%d:T%d)\n", pr->id, 80 pr->limit.state.px, pr->limit.state.tx)); 81 82 end: 83 if (result) 84 printk(KERN_ERR PREFIX "Unable to set limit\n"); 85 86 return result; 87 } 88 89 #ifdef CONFIG_CPU_FREQ 90 91 /* If a passive cooling situation is detected, primarily CPUfreq is used, as it 92 * offers (in most cases) voltage scaling in addition to frequency scaling, and 93 * thus a cubic (instead of linear) reduction of energy. Also, we allow for 94 * _any_ cpufreq driver and not only the acpi-cpufreq driver. 95 */ 96 97 #define CPUFREQ_THERMAL_MIN_STEP 0 98 #define CPUFREQ_THERMAL_MAX_STEP 3 99 100 static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg); 101 static unsigned int acpi_thermal_cpufreq_is_init = 0; 102 103 static int cpu_has_cpufreq(unsigned int cpu) 104 { 105 struct cpufreq_policy policy; 106 if (!acpi_thermal_cpufreq_is_init || cpufreq_get_policy(&policy, cpu)) 107 return 0; 108 return 1; 109 } 110 111 static int acpi_thermal_cpufreq_increase(unsigned int cpu) 112 { 113 if (!cpu_has_cpufreq(cpu)) 114 return -ENODEV; 115 116 if (per_cpu(cpufreq_thermal_reduction_pctg, cpu) < 117 CPUFREQ_THERMAL_MAX_STEP) { 118 per_cpu(cpufreq_thermal_reduction_pctg, cpu)++; 119 cpufreq_update_policy(cpu); 120 return 0; 121 } 122 123 return -ERANGE; 124 } 125 126 static int acpi_thermal_cpufreq_decrease(unsigned int cpu) 127 { 128 if (!cpu_has_cpufreq(cpu)) 129 return -ENODEV; 130 131 if (per_cpu(cpufreq_thermal_reduction_pctg, cpu) > 132 (CPUFREQ_THERMAL_MIN_STEP + 1)) 133 per_cpu(cpufreq_thermal_reduction_pctg, cpu)--; 134 else 135 per_cpu(cpufreq_thermal_reduction_pctg, cpu) = 0; 136 cpufreq_update_policy(cpu); 137 /* We reached max freq again and can leave passive mode */ 138 return !per_cpu(cpufreq_thermal_reduction_pctg, cpu); 139 } 140 141 static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb, 142 unsigned long event, void *data) 143 { 144 struct cpufreq_policy *policy = data; 145 unsigned long max_freq = 0; 146 147 if (event != CPUFREQ_ADJUST) 148 goto out; 149 150 max_freq = ( 151 policy->cpuinfo.max_freq * 152 (100 - per_cpu(cpufreq_thermal_reduction_pctg, policy->cpu) * 20) 153 ) / 100; 154 155 cpufreq_verify_within_limits(policy, 0, max_freq); 156 157 out: 158 return 0; 159 } 160 161 static struct notifier_block acpi_thermal_cpufreq_notifier_block = { 162 .notifier_call = acpi_thermal_cpufreq_notifier, 163 }; 164 165 static int cpufreq_get_max_state(unsigned int cpu) 166 { 167 if (!cpu_has_cpufreq(cpu)) 168 return 0; 169 170 return CPUFREQ_THERMAL_MAX_STEP; 171 } 172 173 static int cpufreq_get_cur_state(unsigned int cpu) 174 { 175 if (!cpu_has_cpufreq(cpu)) 176 return 0; 177 178 return per_cpu(cpufreq_thermal_reduction_pctg, cpu); 179 } 180 181 static int cpufreq_set_cur_state(unsigned int cpu, int state) 182 { 183 if (!cpu_has_cpufreq(cpu)) 184 return 0; 185 186 per_cpu(cpufreq_thermal_reduction_pctg, cpu) = state; 187 cpufreq_update_policy(cpu); 188 return 0; 189 } 190 191 void acpi_thermal_cpufreq_init(void) 192 { 193 int i; 194 195 for (i = 0; i < nr_cpu_ids; i++) 196 if (cpu_present(i)) 197 per_cpu(cpufreq_thermal_reduction_pctg, i) = 0; 198 199 i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block, 200 CPUFREQ_POLICY_NOTIFIER); 201 if (!i) 202 acpi_thermal_cpufreq_is_init = 1; 203 } 204 205 void acpi_thermal_cpufreq_exit(void) 206 { 207 if (acpi_thermal_cpufreq_is_init) 208 cpufreq_unregister_notifier 209 (&acpi_thermal_cpufreq_notifier_block, 210 CPUFREQ_POLICY_NOTIFIER); 211 212 acpi_thermal_cpufreq_is_init = 0; 213 } 214 215 #else /* ! CONFIG_CPU_FREQ */ 216 static int cpufreq_get_max_state(unsigned int cpu) 217 { 218 return 0; 219 } 220 221 static int cpufreq_get_cur_state(unsigned int cpu) 222 { 223 return 0; 224 } 225 226 static int cpufreq_set_cur_state(unsigned int cpu, int state) 227 { 228 return 0; 229 } 230 231 static int acpi_thermal_cpufreq_increase(unsigned int cpu) 232 { 233 return -ENODEV; 234 } 235 static int acpi_thermal_cpufreq_decrease(unsigned int cpu) 236 { 237 return -ENODEV; 238 } 239 240 #endif 241 242 int acpi_processor_set_thermal_limit(acpi_handle handle, int type) 243 { 244 int result = 0; 245 struct acpi_processor *pr = NULL; 246 struct acpi_device *device = NULL; 247 int tx = 0, max_tx_px = 0; 248 249 250 if ((type < ACPI_PROCESSOR_LIMIT_NONE) 251 || (type > ACPI_PROCESSOR_LIMIT_DECREMENT)) 252 return -EINVAL; 253 254 result = acpi_bus_get_device(handle, &device); 255 if (result) 256 return result; 257 258 pr = acpi_driver_data(device); 259 if (!pr) 260 return -ENODEV; 261 262 /* Thermal limits are always relative to the current Px/Tx state. */ 263 if (pr->flags.throttling) 264 pr->limit.thermal.tx = pr->throttling.state; 265 266 /* 267 * Our default policy is to only use throttling at the lowest 268 * performance state. 269 */ 270 271 tx = pr->limit.thermal.tx; 272 273 switch (type) { 274 275 case ACPI_PROCESSOR_LIMIT_NONE: 276 do { 277 result = acpi_thermal_cpufreq_decrease(pr->id); 278 } while (!result); 279 tx = 0; 280 break; 281 282 case ACPI_PROCESSOR_LIMIT_INCREMENT: 283 /* if going up: P-states first, T-states later */ 284 285 result = acpi_thermal_cpufreq_increase(pr->id); 286 if (!result) 287 goto end; 288 else if (result == -ERANGE) 289 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 290 "At maximum performance state\n")); 291 292 if (pr->flags.throttling) { 293 if (tx == (pr->throttling.state_count - 1)) 294 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 295 "At maximum throttling state\n")); 296 else 297 tx++; 298 } 299 break; 300 301 case ACPI_PROCESSOR_LIMIT_DECREMENT: 302 /* if going down: T-states first, P-states later */ 303 304 if (pr->flags.throttling) { 305 if (tx == 0) { 306 max_tx_px = 1; 307 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 308 "At minimum throttling state\n")); 309 } else { 310 tx--; 311 goto end; 312 } 313 } 314 315 result = acpi_thermal_cpufreq_decrease(pr->id); 316 if (result) { 317 /* 318 * We only could get -ERANGE, 1 or 0. 319 * In the first two cases we reached max freq again. 320 */ 321 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 322 "At minimum performance state\n")); 323 max_tx_px = 1; 324 } else 325 max_tx_px = 0; 326 327 break; 328 } 329 330 end: 331 if (pr->flags.throttling) { 332 pr->limit.thermal.px = 0; 333 pr->limit.thermal.tx = tx; 334 335 result = acpi_processor_apply_limit(pr); 336 if (result) 337 printk(KERN_ERR PREFIX "Unable to set thermal limit\n"); 338 339 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Thermal limit now (P%d:T%d)\n", 340 pr->limit.thermal.px, pr->limit.thermal.tx)); 341 } else 342 result = 0; 343 if (max_tx_px) 344 return 1; 345 else 346 return result; 347 } 348 349 int acpi_processor_get_limit_info(struct acpi_processor *pr) 350 { 351 352 if (!pr) 353 return -EINVAL; 354 355 if (pr->flags.throttling) 356 pr->flags.limit = 1; 357 358 return 0; 359 } 360 361 /* thermal coolign device callbacks */ 362 static int acpi_processor_max_state(struct acpi_processor *pr) 363 { 364 int max_state = 0; 365 366 /* 367 * There exists four states according to 368 * cpufreq_thermal_reduction_ptg. 0, 1, 2, 3 369 */ 370 max_state += cpufreq_get_max_state(pr->id); 371 if (pr->flags.throttling) 372 max_state += (pr->throttling.state_count -1); 373 374 return max_state; 375 } 376 static int 377 processor_get_max_state(struct thermal_cooling_device *cdev, char *buf) 378 { 379 struct acpi_device *device = cdev->devdata; 380 struct acpi_processor *pr = acpi_driver_data(device); 381 382 if (!device || !pr) 383 return -EINVAL; 384 385 return sprintf(buf, "%d\n", acpi_processor_max_state(pr)); 386 } 387 388 static int 389 processor_get_cur_state(struct thermal_cooling_device *cdev, char *buf) 390 { 391 struct acpi_device *device = cdev->devdata; 392 struct acpi_processor *pr = acpi_driver_data(device); 393 int cur_state; 394 395 if (!device || !pr) 396 return -EINVAL; 397 398 cur_state = cpufreq_get_cur_state(pr->id); 399 if (pr->flags.throttling) 400 cur_state += pr->throttling.state; 401 402 return sprintf(buf, "%d\n", cur_state); 403 } 404 405 static int 406 processor_set_cur_state(struct thermal_cooling_device *cdev, unsigned int state) 407 { 408 struct acpi_device *device = cdev->devdata; 409 struct acpi_processor *pr = acpi_driver_data(device); 410 int result = 0; 411 int max_pstate; 412 413 if (!device || !pr) 414 return -EINVAL; 415 416 max_pstate = cpufreq_get_max_state(pr->id); 417 418 if (state > acpi_processor_max_state(pr)) 419 return -EINVAL; 420 421 if (state <= max_pstate) { 422 if (pr->flags.throttling && pr->throttling.state) 423 result = acpi_processor_set_throttling(pr, 0); 424 cpufreq_set_cur_state(pr->id, state); 425 } else { 426 cpufreq_set_cur_state(pr->id, max_pstate); 427 result = acpi_processor_set_throttling(pr, 428 state - max_pstate); 429 } 430 return result; 431 } 432 433 struct thermal_cooling_device_ops processor_cooling_ops = { 434 .get_max_state = processor_get_max_state, 435 .get_cur_state = processor_get_cur_state, 436 .set_cur_state = processor_set_cur_state, 437 }; 438 439 /* /proc interface */ 440 441 static int acpi_processor_limit_seq_show(struct seq_file *seq, void *offset) 442 { 443 struct acpi_processor *pr = (struct acpi_processor *)seq->private; 444 445 446 if (!pr) 447 goto end; 448 449 if (!pr->flags.limit) { 450 seq_puts(seq, "<not supported>\n"); 451 goto end; 452 } 453 454 seq_printf(seq, "active limit: P%d:T%d\n" 455 "user limit: P%d:T%d\n" 456 "thermal limit: P%d:T%d\n", 457 pr->limit.state.px, pr->limit.state.tx, 458 pr->limit.user.px, pr->limit.user.tx, 459 pr->limit.thermal.px, pr->limit.thermal.tx); 460 461 end: 462 return 0; 463 } 464 465 static int acpi_processor_limit_open_fs(struct inode *inode, struct file *file) 466 { 467 return single_open(file, acpi_processor_limit_seq_show, 468 PDE(inode)->data); 469 } 470 471 static ssize_t acpi_processor_write_limit(struct file * file, 472 const char __user * buffer, 473 size_t count, loff_t * data) 474 { 475 int result = 0; 476 struct seq_file *m = file->private_data; 477 struct acpi_processor *pr = m->private; 478 char limit_string[25] = { '\0' }; 479 int px = 0; 480 int tx = 0; 481 482 483 if (!pr || (count > sizeof(limit_string) - 1)) { 484 return -EINVAL; 485 } 486 487 if (copy_from_user(limit_string, buffer, count)) { 488 return -EFAULT; 489 } 490 491 limit_string[count] = '\0'; 492 493 if (sscanf(limit_string, "%d:%d", &px, &tx) != 2) { 494 printk(KERN_ERR PREFIX "Invalid data format\n"); 495 return -EINVAL; 496 } 497 498 if (pr->flags.throttling) { 499 if ((tx < 0) || (tx > (pr->throttling.state_count - 1))) { 500 printk(KERN_ERR PREFIX "Invalid tx\n"); 501 return -EINVAL; 502 } 503 pr->limit.user.tx = tx; 504 } 505 506 result = acpi_processor_apply_limit(pr); 507 508 return count; 509 } 510 511 struct file_operations acpi_processor_limit_fops = { 512 .owner = THIS_MODULE, 513 .open = acpi_processor_limit_open_fs, 514 .read = seq_read, 515 .write = acpi_processor_write_limit, 516 .llseek = seq_lseek, 517 .release = single_release, 518 }; 519